Spray nozzles of the type used herein are well known and have been used in a wide variety of applications, including spray drying, exhaust gas scrubbing and snow making, to name just a few. One known multi-port spray nozzle adapted to atomize a gas/liquid mixture is illustrated in FIG. 1. The nozzle 10 shown in FIG. 1 has a sleeve insert 40 in accordance with the present invention. The spray nozzle is manufactured and sold by Turbotak, Inc. of Waterloo, Ontario, Canada under license from Caldyn Apparatebau GmbH, Ettlingen, Germany.
The atomization of solids-containing liquids, such as a lime slurry, can be extremely abrasive on the nozzles, and in particular on the atomization ports of the nozzles. When used in these applications, the spray nozzles are typically sold with sleeve-like inserts which are adapted to fit within the atomization port or ports and to be removed and replaced after they become worn. The Turbotak nozzles have to date been sold with replaceable sleeve inserts having a different design from the sleeve insert 40 illustrated in FIGS. 1 and 2. The Turbotak inserts have a downstream end which is substantially flush with the forward face of the spray nozzle. The downstream end of the Turbotak insert has a flat annular surface which is fairly wide, having a thickness on the order of about 1/4 to 1/2 inch, as measured along an outer diameter of the insert.
Unfortunately, the Turbotak nozzle and insert have experienced problems when used to spray a solids-containing liquid such as a lime slurry. When spraying a lime slurry, lime quickly begins to build-up on the wide downstream annular face of the insert and on the forward face of the nozzle. In many cases the build-up starts to form within just a few hours after spraying has begun. The lime build-up eventually has an adverse effect on the atomization properties of the spray nozzle. Once this occurs, the nozzle must be shut down in order to remove the solids built up on the inserts and the forward face of the nozzle. In severe cases the inserts must be entirely replaced. With certain types of solids-containing liquids, such as lime slurries, the nozzles have to be shut down every few days in order to perform the cleaning/replacement procedure, making the nozzles commercially unacceptable in these applications.
Accordingly, it is an object of the present invention to provide a replaceable nozzle insert which is not subject to the solids build-up problem of the prior art inserts. It is a further object of the invention to provide a replaceable nozzle insert which can be left in operation for longer periods of time without requiring shutting down the nozzle in order to clean and/or replace the nozzle and the inserts.